Re: Window function bug

Excerpts from Tom Lane's message of mar jul 12 11:20:39 -0400 2011:
> I wrote:
> > ... so I guess the answer is that this code ought to avoid adding Vars that
> > are only mentioned within aggregates.
>
> The cleanest way to fix this would involve adding another flag parameter
> to flatten_tlist and pull_var_clause.  This is no problem to do in HEAD
> or even 9.1, but I'm a bit worried about breaking third-party code if we
> backpatch further than that.  So far as I can see, the failure only
> occurs if we have a plain (non-grouping) Agg node, which implies that
> the user is trying to use windowing functions on a result set that's
> guaranteed to contain exactly one aggregated row.  That seems pretty
> useless, so I'm thinking it's not worth back-patching a fix for.
> Comments?

Since there have been no previous bug reports on this, it seems clear
that a backpatch is not strictly necessary either.

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Álvaro Herrera <alvherre@commandprompt.com>
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